Hi, okay, we consider these fish subsistence living!
Aren't we lucky?
Anyway, you can get waxed boxes at several places here in Anchorage including a couple of supermarkets. The gel packs will remain very cold if not still icy for 24 hours - I have to use them for meds.
DO NOT send the fish as cargo! Some friends in Switzerland had their fish held up by customs when they shipped it as cargo and, of course, no one at customs put it in a freezer so it thawed while it sat there for about a week. All ruined! I suppose if you can go immediately upon landing to the cargo offices and the customs house to retrieve your box it might be okay but it's much easier to just take it as checked baggage. That brings back funny memories of going to the customs house at Gatwick to collect my son's pet turtle when she came from Atlanta many years ago...........
Don't forget to get a roll of duct tape to seal your box and to not put in any item that's metal or could attract a search of the box if they xray it. I will also say that there have been stories the last couple of years of boxes of fish somehow just not making it to their final destination - someone in baggage getting a nice dinner maybe? Obviously put your name and address inside and outside the box as well as some way to attach the baggage tag.
Hope it all works out! Now let me see what's handy in the freezer for dinner...halibut or Copper River red or a nice silver or.......I'll be quiet now.